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From: Pavel Fedin <p.fedin@samsung.com>
To: 'Marc Zyngier' <marc.zyngier@arm.com>,
	'Christoffer Dall' <christoffer.dall@linaro.org>
Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Subject: RE: [PATCH] KVM: arm: Fix crash in free_hyp_pgds() if timer initialization fails
Date: Fri, 06 Nov 2015 17:06:07 +0300	[thread overview]
Message-ID: <008801d1189c$48dbe370$da93aa50$@samsung.com> (raw)
In-Reply-To: <563CB012.3090705@arm.com>

 Hello!

> >> The thing I want to avoid is PAGE_HYP_DEVICE covering some normal S2
> >> mapping, which we *should* flush but that we now end up ignoring?  That
> >> doesn't sound like it can be the case because the device bit is the same
> >> bit for both types of page tables, correct?
> >
> >  Yes, this is exactly what i think. If DEVICE bit is set, then it's somehow
> > device memory and it doesn't need flashing.
> >
> >  Or, in order to be 200% sure, we could modify the whole unmapping logic to carry
> > over a flag, telling whether we are removing normal or HYP mappings. But wouldn't
> > this be much more complicated?
> 
> We could do without that complexity. Also, the test itself is wrong (see
> Ard's patch that was posted this morning for the real fix).

 Good. Saw it, will test it on monday. Indeed, this is better than my approach, and
this is what i actually wanted to do but didn't study the thing deeply enough to
implement.

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia



      reply	other threads:[~2015-11-06 14:06 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-27  7:40 [PATCH] KVM: arm: Fix crash in free_hyp_pgds() if timer initialization fails Pavel Fedin
2015-11-05 15:24 ` Christoffer Dall
2015-11-05 18:38   ` [PATCH] KVM: arm: Don't try to flush hyp-mode device mappings kbuild test robot
2015-11-05 23:11   ` kbuild test robot
2015-11-06  9:32   ` [PATCH] KVM: arm: Fix crash in free_hyp_pgds() if timer initialization fails Pavel Fedin
2015-11-06 11:42     ` Christoffer Dall
2015-11-06 13:43       ` Pavel Fedin
2015-11-06 13:50         ` Marc Zyngier
2015-11-06 14:06           ` Pavel Fedin [this message]

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